Capillary electrophoresis is known. An electrolyte filled capillary is injected with sample. The two distal ends of the sample are each emerged in separate electrolyte baths. Each electrolyte bath is communicated with differing electrode potential sufficient for electrophoresis to occur in the capillary.
Electrophoresis is easy to understand. Typically, differing components of a sample subjected to electrophoresis have differing size and differing electric charge. Dependent upon the size of the particles and their charge, a migration of constituents of a sample occurs along the length of a capillary when the capillary is subjected at its distal ends to differing electrical potentials. The discrete particle migration through the capillary is the sum of two effects.
First, and assuming that the capillary is filled with an electrolyte, an overall flow of electrolyte can and does occur due to the difference in electrical potential across the length of the capillary.
Second, and relative to any overall induced flow in the capillary, individual particles of sample will move relative to one another. This movement constitutes the sought after classification due to electrophoresis.
It will be understood that the electrolyte filling in the capillary can be a liquid subject to overall flow or a gel, which is not usually subject to overall flow.
Typically the sample is placed adjacent one end of a capillary. A detector is placed adjacent the opposite end of a capillary. In the migration of the discrete sample constituents relative to the fluid in the capillary, the discrete constituents each form themselves into discrete flowing "bands". These discrete flowing bands are the product of the electrophoresis that are observed to determine both quantity and quality of the sample.